SS RX7 r2

iTrader: (1)

I'm on my 3rd cat back exhaust system.

I now have the Buschur Racing Magnaflow system. I got it for the power, but it's much more quiet. It also gives me the option to easily swap or remove the muffler for racing.

I also take my family in it and I don't worry about my young son's hearing anymore.

2JZfan

iTrader: (5)

Just another datapoint... I built a custom exhaust with top priority being *NO* drone. It turned out exactly like I wanted. The thing sounds like an electric car until you step on it, then it sounds "nice" but not ridiculous. And this is even with no cat. Anyway, here is what I used:

Helix 3" downpipe, I cut off the cat flange and added a v-band flange instead.

Greddy Evo2 catback, I cut off the front 2-3" where it necks down and instead welded a 3" Vibrant resonator on there. At the front of the resonator I put another v-band flange to mate with the downpipe. The greddy catback has it's own resonator near the muffler, so this system ends up with 2 resonators and a muffler. When I do the new turbo and stroker I may remove this rear resonator because, unlike the vibrant piece, the greddy resonator necks down on the inside putting the ID at less than 3". If I remove that I will likely replace it with a shorter vibrant resonator (12" vs the 18" I used up front) instead of a straight pipe. I hate drone!!

So I guess all of that is just a long-winded way of saying that if you start with a reasonably quiet catback and add a resonator, you can get a really quiet system even with no cat. (With a cat in addition to all of this you wouldn't even know the car was running!)

Hope that helps.

evolovinit

iTrader: (2)

Man, that Greddy is 80mm piping, isn't it? And they neck it down under 3 inches at the resonator? Thats too bad! Please post again if you take that section out and comment on the difference. Significant custom work you've got into that exhaust. I thought I was picky!

Borla offred me a "venturi" - a pipe insert before the muffler that necks down a little and is supposed to change the sound. But they would not guarantee that it would be quieter, only that it would lose a little horsepower.

They also said that their exhaust was good for a 20 percent horsepower gain.

I didn't bother to argue that one...